The present invention relates to an individual authentication device, and relates in particular to technology for utilizing vein patterns obtained by capturing an image of light that passed through the body.
The security of personal information has become viewed as in issue of major importance in recent years. Biometrics authentication has become the focus of much attention as a personal authentication technology for safeguarding security. Biometrics is authentication technology that utilizes the biological information of humans, and is excellent in terms of both convenience and security.
Biometrics authentication technology known in the related art performs authentication by utilizing fingerprints, the iris (of the eye), the voice, the face, veins in the back of the hand or finger veins. Among these examples of the related art, the technology disclosed in Japanese Patent Application Laid-Open Publication No. 2004-265269 for biometrics authentication by using the veins, provides excellent protection against falsification because internal biological information is utilized.
The following description describes in particular a finger vein authentication device. The finger vein authentication device irradiates infrared light onto a finger. After scattering inside the finger, the infrared light passes outside the finger. The finger vein authentication device then captures an image of the infrared light that passed through to the palm side of the finger. The hemoglobin in the blood fluid at this time absorbs the infrared light more than the surrounding tissue. The blood vessels (finger veins) distributed under the skin on the palm side of the finger are therefore visible as a dark shadow pattern (finger vein pattern) in the image captured by the finger vein authentication device. The unique features of this finger vein pattern are registered advance, and the finger vein authentication device then authenticates an individual by finding the correlation between the finger vein pattern presented by the user during authentication, with the pre-registered (finger vein pattern) special features.
A finger vein authentication device of this type that is known in the related art is disclosed in Japanese Patent Application Laid-Open Publication No. 2004-265269. This finger vein authentication device captures an image of the finger veins by irradiating infrared light on the finger from the left and right sides. A method for making the finger vein authentication device compact moreover is disclosed in Japanese Patent Application Laid-Open Publication No. 2008-181570 as a device with a narrow imaging range, and the light source installed on the side below the finger.